Newt Gingrich and Rick Perry have been particularly vocal in their criticisms of the former Massachusetts governor.

"There is something inherently wrong when getting rich off failure and sticking it to someone else is how you do your business," Perry said Monday in South Carolina. "And I happen to think that is indefensible."

What Romney did at Bain Capital was use leverage to acquire companies, improve them, and sell them at a profit. Along the way, several of those companies failed, and some workers lost their jobs.

At the same time, some of the companies Bain Capital invested in did quite well, and Romney helped create millions in profits.

The direct arrow-slinging between candidates has yet to abate, and a 28-minute "documentary" film released Wednesday by a super PAC that supports Gingrich could add fuel to the fire.

But the film -- dubbed the "Bain bomb" -- contains numerous factual errors, including criticism of Romney for events that occurred after he had left the firm and was no longer involved in management decisions.